Problem: Solve for $r$ : $-19 = r - 22$
Answer: Add $22$ to both sides: $ \begin{eqnarray} \\ \hphantom{-19 {+ 22}} &\hphantom{=}& \hphantom{r} \\ -19 &=& r - 22 \\ \\ {+22} && {+22} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ -19 {+ 22} &=& r \\ \end{eqnarray} $ Simplify. $ r = 3$